I am thinking about improving the sound quality of my small bedroom. Mostly I want to keep the voice inside and stop the outside noise from coming in (though it doesn't get noisy very often). There are two big windows with thick curtains to cover them. In this kind of setting, which one between panels and foams should I choose?

Hi, My sense is that to cut the sound going in and out of windows something solid would do better than foam. You might be able to make some sort of interior shutters. Then you could open them to see in and out and close them to reduce the noise. Another possibility is to use some of the 2-3 inch thick construction foam used to insulate walls in new houses. Cut it to just fit loosely in the window opening and put a soft weatherstripping foam around the edge to make it fit snugly. You can cover it with fabric to make it more spouse friendly. Put in it to cut the sound, remove it and stow it out of sight when not needed.

Let's not brick up the windows; I love the sight of my little garden every morning from my room!

My room has some distance to the streets and other houses thanks to the garden. I don't think the neighbors or anyone passing by will hear loud noises from the house, but I want to prevent all kinds of complaints. Does it mean that a thick foam can block sound as good as a solid panel? Foams may be better aesthetically, but I'm not sure if it's worth investing in some.

I recommend glass sliding windows if you don't have them yet. I have it in my room and it does a good job of barring the sound in or out of my room. You can still see the garden without the problem of disturbing the neighbor with the sounds you make in the room.